ASSESSMENT OF MARINE DIESEL ENGINES PERFORMANCE BASED ON CARBON AND NITROGEN OXIDES CONTENT IN EXHAUST GASES

The paper presents the analysis of the regularities of the carbon and nitrogen oxides content in the exhaust gases of marine diesel engines (MDEs) of fishing industry fleet, taking into account the features of their operation (changes of hydrometeorological conditions and technical performance). The factors cause decrease in excess air coefficient during combustion, deterioration in the quality of fuel atomization, mixture formation and combustion. A special feature of mixture formation and combustion processes in MDEs with a volumetric method of mixture formation is the separation of the combustion chamber into a series of macro-volumes, each of which receives fuel from the corresponding nozzle opening. At the same time, the concentrations of fuel and air in terms of jets length and sections of are uneven. The smallest drops are located on the surface of fuel jets and, first of all, are inhibited in the dense and hot environment of the working fluid. The temperature in the combustion zone reaches 2600-2900 K and warms up the fuel contained in the inner layers during the lack of oxygen. As a result, carbon is formed, and at the same time in the surface layers - nitrogen oxides. It is shown that in order to simulate the influence of operating factors, the indicators describing the dynamics of combustion of fuel and those that explicitly take into account the effect of structural and operational factors are suitable. A difference in the regularities of the change in carbon emissions with exhaust gases for engines with supercharging and without it is focused. Dependencies have been proposed for modeling carbon emissions and nitrogen oxides when a supercharged engine is subjected to a load (regulatory) characteristic. The possibility of using indicators for diagnosing the technical condition of internal combustion engine is shown.